[Server] (Re-)Implement missing Notification & Request Handlers

[chr-hertel]

For kicking off this SDK we used the Noticiation and Request handlers shipped with the Symfony MCP SDK and adopted schema component and registry.
But the MCP schema supports way more requests and notifications, that would need handlers as well. On php-mcp side this was the responsibility of the Dispatcher implementation.

Still open are:

• ListResourceTemplatesRequest
  [Server] Add request handler for resource templates #89
• ResourceSubscribeRequest
• ResourceUnsubscribeRequest
• SetLogLevelRequest
• CompletionCompleteRequest
  [Server] Add completion/complete handler, centralize provider logic, and move completion capability #97
• CancelledNotification

And potentially other requests and notification of the protocol.

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Please announce yourself and create corresponding sub-issues before working on a specific handler - so we can avoid duplicate effort.

[rheedwahn]

Hi @chr-hertel i ll like to have a go at this, will reach out if i need additional questions

[ineersa]

One more thing I've noticed while rewriting MCPs https://modelcontextprotocol.io/specification/2025-03-26/basic/utilities/cancellation handler is missing too

[bigdevlarry]

Hi @chr-hertel I can see both classes for ResourceSubscribeRequest and ResourceUnsubscribeRequest exist but the handlers and implementations in the RegistryInterface hasn't been effected?

Q: What will be the expectation of both handlers?

[chr-hertel]

@bigdevlarry For those handlers there's a extra tasks, that's true.

We need to track subscribers of a resource, meaning register them within the handler for ResourceSubscribeRequest and unregister them within the handler for ResourceSubscribeRequest - and: we need to bring in functionality to trigger the ResourceUpdatedNotification which is sent to subscriber of that specific resource.

Pointers in Kyrian's previous package:

• Request handling:
  https://github.com/php-mcp/server/blob/d2c583302c4d08dea887c7cbae49c767b0ce75b9/src/Dispatcher.php#L250-L260
• SubscriptionManager:
  https://github.com/php-mcp/server/blob/d2c583302c4d08dea887c7cbae49c767b0ce75b9/src/Session/SubscriptionManager.php#L7
• Notification handling
  https://github.com/php-mcp/server/blob/d2c583302c4d08dea887c7cbae49c767b0ce75b9/src/Protocol.php#L268-L286

I hope this helps as a kickstart - let us know if you have more questions :)